Two-cycle engine.



'PATENTBD 1330524, 19o?.

W. A. ST. GERMAIN. TWO CYCLE ENGINE.. APBPLIOATIOE FILED HAY 24| 190B.

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. No. 874,634. PATENTED DBO. 24, 1907.

W. A. sT. GERMAIN. TWO CYCLE ENGINE.

APPLIGAIVYION FILD MAY 24,'1906.

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. MII/IA [Nl/ENTO/e Y wiLLiAM A. sT. GERMAIN Ol" GREENVILLE, MAINE.

'BEVO-CYCLE ENGINE.

Specification of Letters Patent.

- Patented Dec. 24, 1 907.

Application filed May 24.1906- Serial No. 318.570. i

To all 'whom 'it may concern.' A

Be it known that I, WILLIAM A. ST. Gna- MA1N, a citizen of the UnitedStates, residing at Greenville, in the county oi Piscataquis and Stateof Maine, have invented a new and L useful TwolCycle Engine, of whichthe following is aspeciiication.

This invention relates to two cycleinternal combustion engines, and .hasfor its principal object to provide a double piston two cycle engine sodesigned as to secure two working strokes for each revolution. oi. thecrank shaft.

A further object of the invention is to provide a double piston twocycle engine in which the compression chambers are ar-` ranged forconnection with a single source of supply, such for instance as acarbureter, and y further to provide for the more positive closing andseating of the valves which control communication between the source ofsupply and the compression chambers.

With these and other objects iii view, as

will more fully hereinafter appear, the invention cons-ists in certainnovel features of coni struction and arrangement of parts, hereinl afterfully described, illustrated in the accompanying drawings, andparticularly pointed out in the appended claims, it being understoodthat various changes inthe form, proportions, size and minor 'details ofthe strucvture may be made without departing from the spirit-orsacrificing any of the-advantages yof the invention. Y

In. the accompanying drawings Figure 1 is a sectional elevation of a twocycle engine constructed in accordance with the invention.

the same taken on the plane at right a les to the section of Fig. 1 Fig.3 is a plan view of the engine.

Similar numerals of reference are employed to indicate correspondingparts throughout the several figures of the drawings.

The upper and lower cylinders 10 and 1l are preieijablycast integralwith the upper y be introduced into the lower cylinder are compressed.

Arranged within the upper and lower cylindeis :ire pistons 16 and 17,respectively, said pistons being rigidly connected to Fig. 2 is avertical sectional' view of each I l other by. a rod 18, and the lowerpiston being connected to the crank shaft by a rod 1.9.

; throughpstuling boxes 20 formed at the ad. jacent end of the twocylinders, said stuiiing boxes being preferably .arranged to containmetallic rings 21 that are held in place'by gland nuts 22, although anyother suitable torni oi' b ox may be employed for the pur' pose ofpreventing leakage between the ex- V'lflie cylinder heads' arev spacedfrom each other by a water .chamber 23, in communication with the outerwater. jacket 24 that surrounds the explosion chambers .of bothcyllinders, any suitable connection being eml ployed to promote thecirculation`of water through the jacket.

The main casting is preferably so formed as to include a portion of a.compression 'The .pieten rod 18 is arranged to travel plosion chambersand' the two cylinders.

chamber 25 that ,is in free communication with the upper open end of thecylinder 10,

a .boss 27- on the upper end of the cylinder, and such other connectionsas may be necesi sary. The chamber 25 communicates with the upper end ofthe cylinder l() through the space s 26 on opposite sides of the boss27', Fig. 2. The lower compression chamber communicates with. the upperend of the cylinder 11 through a port V2S which is opened by the piston17, as the' latter completes its down or in stroke, and the compressionchamber 25' is placed in communication. with the lower end of thecylinder 10 by'a port 29 that is opened by piston 16, as the lattercompletes its upward or out stroke, and the pistons are provided with-the usual deflecting plates 30v for the-purpose of diigecting the freshcharges toward the heads of the explosion chambers.

Leading from the two cylinders at points diametrically opposite theinlet ports 28 and 29 are exhaust ports 33 and 14 which com municatewith an exhaust pipe 35, and said exhaust pipe may be reversed in orderto direct the exhausted gases upward. instead of downward, as showminFig. l.

At one side of the cvlindei's is arranged a valve casing 36 Athatpreferably is cylindrical inV lorni and is divided by a pair of par.

held in place by a suitable bolt 27, entering l or other suitable sourceof supply. The i of the engine is a working stroke, and two upperchamber is connected by a pipe to the compression chamber 25 of theupper cylinder, While the lower 'chamber of the valve casing isconnected by a pipe 41 to thecranl casing or compression chamber of thelower cylinder. The two ported partitions 37 and 38 are provided withoppositely facing valve seats 46 and 47', and have guides e5 for thereception of a slidable valve stem 45 having two oppositely facingvalves 46 and 47, one of lwhich is a1- ways closed, while the other isopen.

ln the operation of the engine as thus far described, it will be seenthat when the parts are in the positions shown in Fig. 1, the

upper piston 16 has completed a working stroke, and the products ofcombustion are escaping through the port 34, while the fresh charge isentering the cylinder through the port 29, and at this time the valve 46is held K closed by the pressure ofgas or erqylosive mixture in saidchamber The lower` piston 17 has `iust completed an up or .vorlringcompression stroke, and the compressed charge in the upper portion o'rlthe cylinder about being ignited.v this upward stroke oi the lowerpiston has created a partial vacuum within the lowerconniressionchainber, resulting in the opening of the valve 47, so that a freshcharge may tlcw from the carburetor into the cranlr easing. \\,"hcn thecharge is ignited in the upper end ol the eviinder 1l, the piston ,17will be l'orced down and. will compress the charge pre.` nisly drawninto the cranlr casing, and the increase in pressure 'which results inthe lower portion ol the valve ,casing 36 tends to more the Valve l? toclosed position. At the same time downward nuwement ol' the piston 16 iscreating a partial vacuum in the chamlur 255, so that there is atendency to lili. the valve 45T, and these l'orccs, operaiingsimultaneously on the valves, will more valve i7 posi iveiy to closedposition and will open the valve 1.6, so that a fresh charge may il'lowfrom the carburetor into the chamber 25 as the down stroke continues.vwhen the piston 17 near the limit ci its down strolre, the escape port33 is opened and thel products of combustion will start to escape fromthe cylinder 11, and on slight'lurther 'movement, the irdet port- 26will be opened and the i'resh charge of gas entering the upper end ofthe cylinder will be directed by the deliector 30 toward the head ot'the efr- `plosion chamber and will act to sweep out all or the greaterpart of the exhaust gases through the port 33, so that when the upstroke of the piston 17 commences,V and 'the ports are closed, thecylinder will contain nothing but die fresh charge oil gas.. When the dewn stroke of the piwon is completed, the charge in the upper chamber l0is compressed and is ignited, so that each stroke .suitable manner, andin Fig. 2 jump spari crasse working strokes will occur for eachrevolution of the cranlr shaft. A

' The working charges may be ignited in an.

plugs 5() have been shown in recesses near the heads of the explosionchambers. ".hese are suitably connected to an adjustable c ommutator 51that is disposed at the upper end of a vertical shaft 52 comiected by askew gearing 55 to the main shaft.

It will bel seen that no valves are employed in this engine, with. theexception of those between the compression chambers and the carbureteror other source of supply, and thathan engine of practically' double thehorse power of a single acting two cycle engine is secured, and theweight is but slightly greater than that ot a single acting engine.

l claim ,t 1. ln an internal combustionengine, a pair of cylindersarranged head to head and in alinemcnt with each other, pistons in saidcylinders, a piston rod extending through the head cylinder' and towhich both pistons are secured, a crank shaft connected to one of thepistons, upper and lower compression chambers connected to the open endsof the cylinders, inlet ports leading from the compression chambersthrough the Walls or" the cylinders, exhaust ports leading from thecylinders and arranged to be uncovered by the pistons at` the outerlimits of their strolr-es, all of said ports being controlled by thepistons, a valve chamber intermediate the compression chambers andhavinfr a fluid inlet, and valves arranged in sai Valve chamber andcontrollingl communication between the latter and the compressionchambers.

2. in an internal combustion engine, a pair of cylinders arranged tandemand having their explosion chambers adjacent to each other, a crankcasing in communication with the open end of the inner cylinder, andforming a compression chamber, a second compression chamber in freecommunication with the open end of the other cylinder, piston controlledinlet ports leading from the compression chambers to the respectivecylinders, exhaust ports leading fromv the cylinders, a valve casing incommunication With a source of' supply and with the two compressionchambers, and connected and simultaneously acting valves arranged insaid casing for alternately placing the chambers in communication withthe source of supply.

3. ln an internal combustion engine, a pair of cylinders arrangedtandem, compression chambers in communication with the open ends ,of thecylinders, ports leading from the` compression chambers through thewalls of said cylinders, exhaust ports also leading through the Walls ofthe cylinders, a pair ci connected pistons disposed in said cylindersand controlling the ports, a valve casing in communication with a sourceof supply, and with the two compression chambers, and a pair of valvesarranged. in said valvel chamber, said valves being simultaneously actedupon by the pressure from one `chamber and the suction or partial vacuumthrough the stuiling boxes, pistons secured to the rod and arrangedwithin-the cylinders,A

upper and lower compression ychambersin communication with the open endsoi the chambers adjacent to each lower. compression chambers, connectedvalves adapted to the seats, valves being exposed to the pressure of onechamber and the suction or partial vacuum simultaneously formed in theother chamber.

5. ln an internal combustion engine, the combination with. a pair ofcylinders, pistons therein, a pairof chambers connected to saidcylinders, the pistons operating to simultaneously produce a partialvacuum in one of the chambers. and a compression in the other chamber, abranched supply conduit connected with. the chambers, a valve casing atthe point of branching ol the conduit, valves in the casingforcontrolling the sup- 2 ply through each branch ol the conduit,and

a piston rod extending cylinders, piston controlled inlet ports lea'd-'l ing from said chambers to the ton. controlled exhaust ports .leading-lroni the cylinders, a valve casing, having ported cylinders, pislpartitions and provided with valve seats, 2 said casing being incommunication with. a i

source of supply and with the upper and means for connecting the valvesmulta-neously by the combined eilect of the vacuum iii one chamberandthe compression in. the other.

ln testimony that l claim the vforegoing as my own, l. have heretoaffixed my signature in the presence of two witnesses.

l WILLIAM A. ST. ("rllMAlN.

Witnesses'. l`. 7. ALLEN, ll. M. SHAW.

land a pair of said`

